Have you reviewed your course material for the solutions?

It's highly propable that your course material already provides you with all the information you need to tackle these tasks.

perl "-aF:|\s" -nE"$h{shift @F}+=shift @F while @F}{say qq|$_\t=$h{$_}
+| for keys %h"  YOUR-FILE-NAME.txt
[download]

On the other hand, if you do take the trouble of researching each construct used in that code, you could learn a great deal, and if you have trouble understanding a particular aspect, we would be glad to help.

Hi AwesomePerson,
Welcome to the Monastery.
As much as perlmonks help in various ways, out rightly doing your work for you is not one of such.
Believe me, if you give all of your proposed work some trial you will be surprised the legions of monks at your service helping you grow.
Please check How do I post a question effectively?.
Hope this helps.

Here's an answer, not necessarily the best, to PART 2, at least the string transformation portion thereof, but I'd strongly suggest you understand all of it before submitting it to your instructor lest embarrassing questions be asked. (See List::Util for the  sum() function)

>perl -wMstrict -le
"use List::Util qw(sum);
 ;;
 my $s = 'r1y2g3g4y2r4r3y5y3g3g6g2r1';
 my $r = 'r 1 y 2 g 7 y 2 r 7 y 8 g 11 r 1 ';
 ;;
 $s =~ s{ (([[:alpha:]]) \d+ (?: \2 \d+)*) }
        {$2 ${ \sum $1 =~ /\d+/g } }xmsg;
 print qq{'$s'};
 ;;
 $s eq $r or die 'not what was wanted';
"
'r 1 y 2 g 7 y 2 r 7 y 8 g 11 r 1 '
[download]

Notice that I had to cheat a bit to make this work: the extra space at the end of the  $r "required output" string. Can you alter the substitution to get rid of this extra space, perhaps by adding a  (\z)? or  (\Z)? term to the regex and modifying the replacement expression accordingly?

LOL! Not even bothering to rephrase the question, it is cut and pasted directly from the homework assignment.