In article ,
micky wrote:

Does that also have to be R, RMA, or RA?

Either Rosin Activated or Rosin Mildly Activated will be fine. Don't buy
any acid flux.

But the paste you already have should be fine. If you want it to be
liquid, just mix it with some alcohol. (IPA is fine, but get the pure
stuff if you can, not the 70% stuff.)

If you're soldering iron tip isn't shiny new, put a shiny new tip on it.
It will make a surprisingly large difference in the ease and quality of
your soldering.