How do you know what there they're and all the other ones needs to be used

Any french speakers? i need some . how would i say 'my oldest brother is very tall, interesting, and good at drawinng.' in french? would it be: mon (i don't know the french word for oldest) frère est très grand, intéressant, et bon à dessin. also, how would i say 'my dad is good at his work' in french?

Describe some friends and family members and your relationships with them. (this is for french but answer in english)

Choose the correct conjugation of the verb between parenthesis in passe compose. elles (marcher) toute la journee.* sont marchees* ont marche* ont marches* ont marcheeschoose the correct conjugation of the verb between parenthesis in passe compose. il (monter) dans le train. * amonte* est montee* est monte* est monti