All you have to do is open the minecraft multiplayer, put the ip in and you should be on manacube. The reason why you are shown manacube instead of minevast is because minevast's name was changed to manacube.
The ip is:
ok great, perfect, thanks....one more question, what's the deal with tlauncher, do the manacube servers not work thru tlauncher? i'm more familiar with roblox than with minecraft...do you have to pay for minecraft to have access to all servers, or is there a free version?
Minecraft costs money to buy, a free version is called an Alt, or an Alternative account. Once minecraft is bought you can search Minecraft in the search bar of your computer and click the icon, then the launcher will open.
Once the launher is open, you log in with your account details such as password and account name (often referred to as ign - in game name) then you’ll have to change versions as Manacube uses 1.12 which isnt the most recent update, 1.13.2 is.
It seems very complicated but trust me its easy to adjust to!
I suggest just getting to know minecraft itself before joinging Manacube as it’s not necessarily ideal for very new players to Minecraft as it has extra features & is just generally a good idea to know the basics. Hope this was helpful!