Need help relating forms!!!!!

Need help relating forms!!!!!

Hi, I a new to this but here is my problem:

I created a form (Requerimientos) that is going to be filled by some person, then I created another form (Informe) that is going to contain the info that was filled on Requerimientos.

I am trying to place a lookup field and opens the box where asks me to select the app where I want to get the info, the app is OK but then I cannot find the info I want to get from the other form, it is too general and does not relate to a specific form, therefore I can't get the info I want into the form.

What am I doing wrong?????

Thanks in advance!!