the park tool for removing a freewheel is only needed to remove it. freewheels thread back on without tools. grease on the threads is a good idea. don't cross-thread it.
agreed that buying that tool for a one-time use might be silly. that particular tool is very inexpensive though. if you plan on working on a lot of cheap bikes, it's a good idea to have one. otherwise, a bike shop or co-op can get it popped off the one time and you might never use that tool again. most bikes that are not base-level cheap bikes don't use a freewheel.
t3rm3y is going to need to be more resourceful in finding instructions and reading them on his own to get through this. with all the moving parts in a drivetrain, he needs to be willing to dig in and find specific answers with resources we recommend. online advice only goes so far because any mechanic needs to examine and
touch the bike in question to diagnose and adjust it. if you can't be bothered to look up "how to remove Sunrace freewheel," you need to just drop it off at a bike shop. the techniques and tools needed to do this are not difficult to master, but there's only so much internet hand-holding possible before you need to roll up your sleeves and do it yourself.