Editing video has always been a time consuming process, it's just the nature of working with any time-based media. One thing that speeds this up considerably is using keyboard shortcuts or keystrokes. Every non linear editing program has them programmed in, it's just a matter of learning which key is mapped to which command.
Resolve has a slightly odd mapping of it's own, relying heavily on the Function keys on a keyboard, but this is slightly odd for laptop and small keyboard users as typically the function key is mapped as a secondary key function, which makes it only slightly more efficient than using your mouse. So as a resolution to this, I highly recommend customizing your preferences, even if you're just doing this one time. It will make for a smoother, simpler experience.
If you already have familiarity with Final Cut Pro X, Adobe Premiere, or Avid Media Composer, then it is an option to take one of their configurations. Just select it in the top right hand corner and hit Accept.
If you're totally new to all this, I'm going to list off my recommendations below. Feel free to choose different keys, if you prefer. As you reassign these, they will prompt you if you're double assigning a key, simple unassign the conflicting key just be sure you're not unassigning something you regularly use.
Append Clip to End of Timeline(Edit Application)
Insert Clip(Edit Application)
Add Marker(Edit Application)