Welcome to the Magix user to user forums, so NOT Magix Support.
Please do not post your email address or other confidential data to a public forum like this one! There is a very real danger of your email address being harvested by Spam bots!
The simple answer to your question: log into your Magix account, download and install the app on your new computer, enter any and all serial keys to register and everything currently available on your old machine should now be available to download to your new.
If that does not answer your question, please post back with a lot more information; this post will show you the details which will help us to help you. Don't forget to tell us exactly which version and variant of MM you have.