Translation:I'm looking for a pretty dress for you.
I guess I'm wondering why this doesnt translate to, "I look for a pretty dress for you." I would have thought 'buscando' translates to 'look-ing'
OK, nevermind. I looked it up while I was in the middle of typing this - I was wrong.
If anyone is wondering like I was, apparently, "In Spanish, both the simple present and the present progressive can be used to talk about things happening now."
Yes, interpreting now as meaning use the present tense. Busco could also translate as "I do look for" probably used most in negative (I do not..) or interrogative (do I look for..).
Your initial thought to use the participle in form "estoy buscando" gas much narrower meaning of "I am looking for...[right now, just as you rang to ask me!]"
An even simpler, but not as good of an explanation is that it is a prepositional pronoun. Pronouns that are used after proposition in Spanish are described at https://www.spanishdict.com/guide/prepositional-pronouns-in-spanish.
The list there includes all the usual suspects like él, ella, usted, estedes, etc. Note however, the first person and second person informal prepositional pronouns are different and are mí and ti respectively.
Since para is a preposition and the following pronoun is informal second person, ti must be used. It could have been para mí (for me), para ustedes (for you all), etc.
Adjectives mostly come after the noun they modify in Spanish, but not always. In the case of this lesson the adjective bonito does come after the noun.
The following link will help with adjective placement: