The card has a Mother MX4 standard box connector rather than an edge connector. So to use the board you will need a Mother X4 or compatible expansion card.
This is a fully open source project and all code and more documentation is available on the project's [https://github.com/revaldinho/cpc_ram_expansion GitHub pages] and [https://github.com/revaldinho/cpc_ram_expansion/wiki/CPC-512K-RAM-Expansion wiki.]
The bare PCB is available from SeeedStudio via their [https://www.seeedstudio.com/Amstrad-CPC6128-512K-RAM-Expansion-Card-g-1136535 Seeed Gallery pages].