Some of my students were not sure what verb stem (V.S.) is. So, I would like to introduce what it is. Simply, I can tell you that v.s. is without 다/da of verb infinitive.  For instance, verb stem of “To eat/먹다/meok da” is 먹/meok.  Verb stem of “To see/보다/bo da” is 보/bo.  A few weeks ago, I posted how to use “Want to/ 고 싶다/go sip da” with verb stem, and grammar point is “V.S. + 고 싶다.”  As I explained you can remove the 다/ da and add new expression, so it becomes 보고 싶다.  Is it clear what V.S. is now? If not, please read more examples below.

To meet 만나다

V.S. is 만나     만나 + 고 싶다  = 만나고 싶다

To do 하다

V.S. is 하        하+고 싶다 = 하고 싶다

To go 가다

V.S. is 가       가 +고 싶다 = 가고 싶다

I think it will be helpful to understand the verb stem in learning Korean grammars. If you have any question, please let me know.