How would you say be in spanish?

Just add "-ría (yo), -rías (tú), -ría (usted / él / ella / ello / eso / esto / aquello...), -ríamos (nosotros), -ríais (vosotros), -rían (ustedes / ellos / ellas / ésos / éstos...)" at the end of the verb when it's conjugated in future:

Querré / querría --- I will want / I would want

Tendrás / tendrías --- You will have / you would have

Comeréis - comeríais --- You will eat / you would eat

You don't...would is a verb tense...so it means modifying the ending of a verb.

For example, to be is "ser"

I will be is seré

I would be is sería

So you see the term "would" has to be in conjunction with whatever verb the noun is "doing"