Claiming Rewards- Questions

Okay, been playing for a while and now have some points I want to use for our upcoming trip.
My questions are
A- Do I just claim the reward on my phone and show that somehow (email/screenshot, etc..) to someone or do I have to print something.
B- If I have to show something, can I make the claim days ahead or do I have claim the reward while I'm at the casino?
C- Once I have claimed the reward, how do I trade it in to use it? Do I have to take my phone/printout to the players rewards desk or do I just take it to the place to use it (restaurant, etc..)?

Thanx in advance for your help. Any other suggestions you can offer would be greatly appreciated.
A-One you purchase a reward it will be in the "wallet" section on MYVegas mobile and it will have a code associated with it.
B & C-The day you want to use the reward you go up to the M-Life booth of the Casino the reward is for and show them the code.
They will then put that code on your M-life card. When you go to use it just give your M-life card to the venue or restaurant and they will automatically deduct it off the bill.
Once M-Life puts the reward on your card you have 24 hours to use it or loose it.
If you purchase a reward and decide not to use it you can go back into MyVegas rewards and get refunded for it.
Thank you so much. That makes sense. Trying to find that clearly explained info on their app, not so much.
I have to add if you are booking a hotel or show tickets you only need to call and give them the reward code to redeem. This can be done many months in advance. Once you "book" this is no longer refundable. You can pick up your tickets in advance no later than a couple of hours before the show. If it is a hotel room you just show up and give them the reservation code.

When redeeming at the M life desk I have only given them the reward code no need to print or show anything.

As long as you've got the code, you're generally good to go - as answered by others above.
If my husband gets a free show ticket and I get a free show ticket will I be able to book them so we can sit together?

We had also gotten a mandalay buffet buy one get one and when it came up it had rules and then you agree before you buy it. Once the email came it now says you have to stay one night at mgm to use it?? This was misleading because it was not in the rules at all. I wanted the $50 play at Mandalay but in the rules before you buy it it let you know you had to stay there 3 nights so we are there one night so I did not get it. Is there anyway to return the buffet one so we can use the points on something we can use?

Thanks.

Kathy
I'm pretty sure if you log into your account, there's a way to return unused rewards. I remember doing that about a year ago. In the interest of full disclosure, I've haven't used any MyVegas rewards since last August.
Yes you can cancel any reward before it is used. You just pull it up in the wallet, click cancel, points go back immediately into your account. As far as tickets go...you have to redeem them online through your mlife account. Once redeemed, you can not cancel. If you chose to call them to redeem you will pay a fee to have them do it. When you choose a reward, look closely in the bottom left corner....if there is a key it means you have to be staying in a room. Usually if you look further there will be another buffet, usually twice the amount of points, that can be redeemed without a hotel stay.