Pronunciation of the rolled 'r'

[ARouND]

Hi everyone!
I'm a beginner of Latin. Since it got me in the pronunciation of all the "r"s like the one in "liber" and there's little sources I could find to help me pronounce Latin, I studied the basic pronunciation of Spanish first.

After 2 hours practice, for my knowledge in Spanish is so poor that I cannot even tell if I pronounced it rightly, I turn to here. I made a small video which included my pronunciation of 8 words. 4 are simple "r"s while 4 are hard "r"s(rr?).
<snip> Removed video link <snip>
I also uploaded the audio source in my attachment.

If I did it wrongly, could you please tell me in where I misdid and how to improve my pronunciation of hard r?
Thanks in advance!

P.S. This is my first post here and I do not know if I put it in the proper category. My sincere apologies if I don't.