no problem, use sony mobile flasher for this!
1. download twrp recovery:
https://dl.twrp.me/yuga/twrp-3.0.2-0-yuga.img.html
2. download rom and copy it to SD STORAGE on your phone:
https://basketbuild.com/devs/Chippa_a/yuga/LineageOS-14.x and download gapps 7.1 ofc and copy that too:
http://opengapps.org/
3. open sony mobile flasher and connect your pc
4. press "Storm" icon on app > select fastboot mod > press ok > on the right side on window, press "reboot info fastboot mode (via fastboot)
5. now you have custom recovery, disconnect phone from pc and turn him up while pressing volume + and - fast > wipe whole phone > flash rom and then go back and flash gapps and exit recovery
6. enjoy in new rom