How many variables can I add?

I need to add 6 variables but seems to be stuck on 3, is there anyway to expand that to more?

I believe that 3 is the limit. Of course, you can do a lot by splitting the process to work with three variables at any one time (prompt) and have a multi-step process to be able to work with more.

If you can share more specifics the community may be able to help further with more precisely applicable advice.