A variation of Yvonne's answer:
Explanation, following the steps of the question:
1. You're in a country which contains thousands of soldiers who[m] never fight.
This is the Terracotta Army, so the country is China.
2. You take the 1st number of the name of this country, and subtract lines of 7.
The first letter of 'China' is 'C', which has ASCII code 67. The number of "lines" in the number 7 printed on a digital board is 3. Subtract 3 from 67 to get 64.
3. Under the square tree's stump.
Take the square root of 64 to get 8.
everything down to here has been confirmed by the OP
4. You take this number and find a corresponding key.
The 8th letter key on a (QWERTY) keyboard is 'I'.
5. You go down soh, left stx and concatenate the first key with this one.
SOH (Start of Header) is 1 and STX (Start of Text) is 2, in ASCII code. Start from the I key on your keyboard; go 1 down and 2 left to get to the letter 'G' (or 'H', depending on whether you go down-left or down-right). Concatenate this with the first key to get IG.
6. You are here. What have you made it to?
The town of Ig, Slovenia.