tension spring and ccutter belts

the spring that controls the cutter blades broke and I ordered a new one. the tension makes it hard to get belts back on the rollers. please give me advise on how to get the belt back on

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0