Well there are multiple ways of doing so, though given your friend status I suggest using Dodo codes, A temporary code that you can share to the public. Though you can also exclude them to switch friends.

Once you get a Dodo code set up, the gates will be open untill you speak with Orvile to close them again.

A little word of warning, there are certain things that you can't do when the gates are open, such as rearranging furnature

Okay, may test the Dodo code with someone some time.

Oh I now, I have watched a number of ACNH streams and have seen this. =P

You have to either give out or have someone get a "Friend Code," usually found in the Profile section of your "page" (in the upper left hand corner.) It'll look like "SW-XXXX-XXXX-XXXX." People send friend codes to each other by simply telling others they want to be friends with.

In your page, you'll also see "Add Friend." Go there, and click "Search with Friend Code." Type in the 8-digit Friend Code you received.

My Friend Code is SW-6122-2952-4427

You can also add friends via "Friend Suggestions," if you've linked your Nintendo account to Twitter and Facebook.

Well if what MrBlah above said is correct I may not need to hassle with Friend Codes. =P

Also Twitter and Facebook, haha, I don't have either one. =P

Yeah, the Dodo code implementation is pretty convenient, a simple 5 character code that lasts for as long as those gates are open, that let you vist someone's island or vice versa.
I've done it a couple of times for turnips, but in those circumstances there will be lots of people trying to visit the island at the same time, which is where the networking issues become apparently.
When someone joins via Dodo code, there's a 20-30 second long waiting period with multiple cut scenes. This isn't bad if you're a lone player visiting someone's island, but this gets aggravating when up to seven other people try to visit at the same time, there's no parallel connection process or lobby system to ease this.

Alrighty, I have watched a number of ACNH streams and have seen these load times, but that is fine. It's not like I am gonna have 7 people over at a time, just select people I know personally.
Mostly I am seeking a means to get apples, cherries and the 3 remaining flower types I am lacking. I won't likely buy other peoples stuff from their shop(s) for weird personal reasons.

I have all the fruits, lemme trade for some new flowers :D

Few questions, what flowers do you need?
What flowers do you have? I need mums, lilies and cosmos.
And what is a good time for you?

I have mums and cosmos ^^ ill open right now if you want

Well first is there anything you want/need?

Flower seeds ^^ thats all~ Any kinds you have, and you can sell all the fruit you want from my place to pay for any expenses lost in getting seeds~

Okay, well would you wanna visit my island since I have the gate opened and a Dodo code available?

I can sen you my Switch friend code via notes same for the Dodo code. I am not yet willing to just let anyone and every in. ._.

Sure thing ^^

I could offer my town.

I dont have much in it and honestly i only offer folks visiting so i can get them on my bestfreind list so we can later exchange fossels. Im at the point where duplicates are common and if you got gaps in your collection we can help out

Well the only thing I am currently after is yellow lilies, yellow cosmos, and white mums, preferably seeds from Nook's Cranny.

Given my stubborn nature I am not willing to take fossils and any item that is added to my catalog, so no furniture, wallpaper/flooring, clothes, fossils, music etc.. Flowers are different though.

But really you shouldn't need to rush the museum, if you don't ever visit islands with a different hemisphere as your own you're gonna have to spend almost a year to get all the bugs and fish, not to mention the art that is coming soon. =P

Only playing it cause a friend pulled me into it. It's.... an odd game, but kind of interesting

I've played 2 other Animal Crossing games, so I looked forward to this one. =3

Got the game recently myself, frankly I just wanna craft and do cool things while enjoying the game with friends.

I'm just doing things at my own pace. =P
Like I have been stuck on a 3 star rating and that is fine.

I only just barely got the first townhall, and that was with some time travel shenanigans involved, ehehe.
As long as you're having fun, that's what matters.