open up, put on and hold back

can you explain to me what do , open up , put on and hold back mean?
Maya is very shy s it is hard for her to[color=red] open up at parties .
2-Ari’s music class[color=red] put on a show for the parents .
3-She’s a very reserved person .She tends to[color=red] hold back

“To open up” means to go from being shy by disposition to being talkative, especially concerning yourself. It also means to reveal information about a matter you refused to discuss in detail, lied about or kept secret.

The former public official opened up about his rumored affairs.

“To put on” means to stage or hold an event, especially a performance of some sort.

The singer has put on six concerts in our city.

“To hold back” means to keep one’s thoughts to oneself.

Much as I want to convey my feelings for her, fear of rejection causes me to hold back.

Just to add my two cents for the particles:

Up: to its full level, completely, as if to open the hatch of a hatchback to its full level: up.
On: of one thing covering another in touch, such as clothes covering a body so as to provide a show, in effect, for the clothes.
Back: toward the rear, such as to move back in confrontation with a tiger: acting negatively or back/inwardly.