Sherief wrote: I don't have a footage that was shoot with Multicam or Different Camera angles. I have 1 camera that has a loot of footage (10 clips). Actually putting them in the multicam mode makes everything very laggy, and I don't see how it helps with my case
You said you've got 10 timelines, in which you've synced the audio to each of the 10 videos?
So you could now just make a Multicam from those 10 timelines - ie nesting the timelines in a Multicam. Because the 10 timelines are already synced, so too will be the multicam.
You can either keep the timelines nested in the Multicam, or, once you've placed them in the Multicam, right-click on all the timelines and choose Decompose In Place to bring in the original clips - which will remain synced.
However if you're having performance problems, you might instead want to render those 10 timelines on the Deliver page, in Single Clip mode. Render to a high-quality, low-latency format like ProRes or DNxHR. Then import those 10 newly rendered files, and put them into a Multicam clip. Again they'll already be synced, and each camera angle will have the audio.
If you do the latter, you may not need to worry about making proxies, because the ProRes/DNxHR footage is already fast for editing. If you stick to using the nested timelines (or the original clips Decomposed), then you may well want/need to make proxies for your original video files - and definitely do so if those original videos are in H264 or H265. Editing 10 x H264 or H265 will lag most systems.
Once you have a Multicam Clip, drag it onto a new Timeline on the Edit page. Double click the Multicam clip so it appears in the Source Viewer (the left viewer) , and then in the bottom left of the Source Viewer change the viewer mode to Multicam.
Here's a screenshot of a Timeline of my own, in which I'm editing a Multicam. I've highlighted the Multicam mode icon in the left viewer that needs to be selected.

To make edits, you can now click on the desired 'Angle' in the Source Viewer - I have two angles in my screenshot, labelled 'Abi' and 'Rosanna'. Yours will have 10. That will cut the clip at the playhead to the angle clicked. Or hold Shift and click to switch the angle without placing a cut. These options are also available on the right-click menu for the multicam clip on the timeline.
The control in the bottom right of the Source Viewer labelled 'Default' controls how many angles you see at once. So if you don't see all 10 angles at once, click that and choose 4 x 4 mode instead of 'Default':

Because you've put the same audio with every camera, whatever camera you switch to will have the audio for the song.
Multicam is a really fast and efficient way to edit together multiple cameras. You can hit Play and watch all 10 angles simultaneously in real time, and click angles in the Source Viewer to place cuts whenever you want to change camera. Then you can go through the cuts more slowly, refining their exact position.
As others have mentioned, there's tutorials on all this - and the manual of course.