You posted to the Video area of the forum, under the Other Products heading. Since you have not been able to specify precisely which Magix product you are asking for help with I have moved your post, at least temporarily, to the Off Topic forum. If you come back and say which product you need help with I will move this post to the correct area.
The simple answer to your question is: by using it and so finding out what it can and cannot do; by careful reading of the included Help files; by looking at the tutorials area of this forum; by asking quite specific questions in the appropriate area of the forum!
Also, please read this post so you have some idea of the information we need in order to be able to help you, especially the details of your computer and the specific version and variant of the Magix product you have.
This is a very friendly user to user forum, with many experienced users of the software who will do their best to help you.
Please read this topic and put the following information in your profile signature so we do not have to ask for it:
Computer specification - processor make/model, graphics card or chipset make/model, audio card or chipset make/model, RAM, hard drive configuration and sizes?
Windows version and is it up to date? Press and hold down the Windows key and the R key - in the dialog that opens type in winver and press enter.
Software full name and version number - as found under Help, About . . .
Also when posting please include the following where applicable:
Audio and/or video file formats being imported
Export format and settings used
MediaInfo data on audio or video - see below
If you have issues with importing audio or video please use MediaInfo https://mediaarea.net/en/MediaInfo to analyse a problem clip and post the results from the Tree view in MediaInfo
Also add any other information you think may be relevant.
If you want to post examples of your work with a Magix program there is a separate section of the forum - click the Media option at the top of the page.
The Community rules are to be found using the link at the bottom of the page.
In response to you question - depending on the line of Magix products you are using see the Tutorials section of this forum or the Vegas software forum, there are many 'how to' videos with Magix software on Youtube and there is also the Magix magazine and Vegas magazine which have useful tips, tricks and how to's.