How can I have one field automatically populate another field.

I am looking for help, hopefully I can explain this well enough.

In my Airtable, I have a multiple select field where you can choose different available mediums.  (Video, animation, poster, pdfs etc). And I want to create another column that automatically changes depending on what is selected.  If video or animation is selected, a V would appear in the column next to it.  If a “poster or PDF” is chosen a G would appear.  

I cannot figure out what Formula to use.

Basically I want it to be “if this is selected” then “show this”

I tried creating a formula column and added