I have never had an actual guitar teacher and learn solely through articles on the internet and my own mistakes. As far as this sentence is concerned, a C-G-F-C progression for example (a typical I-V-IV-I progression); , what does the I-V-IV-I mean? I did not know if it was something to do with the major scale.
I'm Always Thinking...

I-V-IV-I means root(the first chord/note in the progression/scale) the fifth of the root, the fourth of the root, and the root.

btw, I have 2 pugs myself!
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They are numbers.
Sorryz for me bad engrish.

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It indeed does have to do with the major scale. If you were to take each note of a major scale and make a chord in the key with each note as the root, you would have a major chord scale. Now, with the progression being a I-IV-V-I, it means that the progression contains the first, fourth, fifth, and first (again) chords in the chord scale.
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The numbers refer to the intervals of the major scale, In this case C major.

The scale is:

So the first interval is C, the 5th is G, the 4th is F.
i had thought that was what it concerned. Thanks
I'm Always Thinking...

To add to what is above - the roman numerals system is pretty useful and there are some other tricks to it.

CAPITALS I IV V mean major
lowercase ii iii vi mean minor
circles/stars above vii* mean diminished

As said before the roman numeral indicates where the root of the chord is relative to the root, but you can also fiddle with the numerals e.g. bvi means play a minor chord a b6 above the root. (in c maj that means Abm)

any more terminology you spot you need help with, just come back