The rear cam has to be slightly rotated forward(1/2 tooth) to get the belt on the correct tooth, use a wrench or breaker bar not a ratchet
I recommend against rotating the rear cam gear clockwise, Rotate the front cam gear counter clockwise to remove & install the timing belt. In Fact.....I stop a little short (One tooth) of TDC at the Crank so the rear cam doesn't jump clockwise on valve spring pressure.
Before removing the old belt, I mark it with a paint pen at the 2 cam gear alignment marks....Then transfer the marks to the new belt.
Start with the rear cam which is still out of position-counter clockwise & secure the belt to the cam gear with the painted mark aligned with the mark on the cam gear (I use a Zip Tie).
Rotate the front cam gear counter clockwise 'till you can slip the belt on with the 2 marks aligned, Secure the belt to the cam gear. Now you can use your small breaker bar & 17mm socket to pull BOTH
cam gears clockwise into alignment.
The crank will still be set a little counter clockwise from TDC.....That's good as you can slip the belt on & turn it clockwise to take up the slack & it will be dead on.
While holding the belt in place......Install the lower Belt Guard as it will keep the belt on the crank gear while you install the Tensioner.
I like to put a flat blade screwdriver between the tensioner & tensioner pulley assembly before pulling the pin & slowly releasing the tensioner.