Music Maker can be installed on a maximum of two devices simultaneously. You need to check your Magix account to see how many activations are recorded on your account and, if necessary, deactivate at least one.
Then, access the same account page on your new computer, where the installation file will be available to download. Install the app, log in with the same details as you used on your old computer and ALL your previously purchased content, instruments, soundpools etc., should be available to you to download and install.
You also ask about "engines". I assume you mean the "audio driver". The MM install will automatically install the "Magix Low Latency" driver; any other driver installation will depend on your audio interface.