Hi there, I'm relatively new to GM for 4th edition. I did start up a VTT and load up the game with a couple supplements. Also purchased a couple supplements from DriveThruRPG to see what folks are doing for the Community. If you're looking to write a beginner's scenario I'd start here:
https://freeleaguepublishing.com/community-content/
Back to question one. What I typically do with any game is try a couple icebreaker sessions. Random encounters that I get together to see how well the PCs adjust to decision making as a team. I pick a couple random encounters with animals or obviously bad intent people as adversaries and see how they handle it. After that, I typically push the content forward to the direction the PCs take it. I picked up 'Soldier's, Farms and Refugees' and find that it has a plethora of point to point encounters that I can roll out ahead of time and build into a night of fun. The size of the group is about like yours, and I'm looking to see if I can condense events leading into a campaign or at least drop several story arc hints for longer play.
My campaign on a Virtual Table Top (VTT) will be a new experience; never done that before and it seems like it lets the players drive a little more than I'm used to. That's a good thing. I'm thrilled at the level of support that Free League put into their #T2k4E offering, and I think it's a smart way forward after third edition got too complex for my PCs to follow (as well as the page flipping nightmare of conflict resolution).
I haven't GM'd in decades (!!) so this will be exciting. I have some veteran bros and their main squeezes who I'm targeting with this, so we'll see how that works out. We all like board games and some of them like table top RPGs but time has been the hardest struggle. Hopefully the VTT will forego the time investment.