New SSD not detected on MacBook Air 7,1
Start recovery mode with CommandOptionR.
Open Terminal, and run below commands:

diskutil list

Find which /dev/diskX is yours, usually disk0. Once you identify your disk, erase it with diskutil

diskutil eraseDisk JHFS+ MacOS /dev/disk0



After this, I was able to restore using Time Machine and even install Mojave, giving me an option to chose internal transcend drive for install

After erasing disk using Disk Utility, Time Machine nor Mojave install was working. Mojave was showing my internal Transcend drive greyed out, but this worked.