Instagram Ads - How much to invest?

Hey guys, i have some questions about Instagram Ads and how i use them efficient.
My friend wanna start own events so renting a Club and making themed partys.
So he asked me to do his instagram and asked me how much € he need to invest in Instagram Ads to make it worth that the Party gonna be a hit.
So my questions are:
How much money he need to invest in ads?
How i use the ads efficient (maybe giveaway)?
Lets say he announce the Party on 1th October on his instagram how long he should running ads so whats the best Period of time between announcement and when the Party going?
Any other tips i should know about?

Thanks for help, i really dont want to put his money in trash

for a start, maybe spend around $10 a day for a week. then, increase it to $20 as you gain some tractions.

These should help you get some insights:
(https://sproutsocial.com/insights/instagram-advertising/)
(https://www.lyfemarketing.com/blog/spend-on-instagram-ads/)