You haven't really told us anything that we need to know in order to be able to advise you properly, but I'm going to guess you are using a recent version of Music Maker (the current latest is 28.0.2.47). Is that correct?
The next stage of my answer is going to be even more speculative! The title of your post suggests you want to make music maker default screen like the old version; inevitable question, which version? However, as a general point, the current settings for the workscreen are not substantially changeable and cannot, I believe, be made to "look like" anything different. (But see below.) However, the text of your post says you want to know how to set the settings to default. Unless I'm misunderstanding something, that is NOT the same as your post title because you are implying you have made changes to your workscreen and now want to revert to the default for whichever version you have. If so, try pressing View>Standard layout (shortcut F4).
That same menu setting, View, does offer you some degree of customisation of your workscreen.
HTH, but if not please post back with rather more detail about exactly what you want help with.