Step by step

Let's say disk1 is OS root file system and disk2 and disk3 is additional volumes.

Probable there is an option without conversion, I prefer to go with native QCOW2 format ;-)

Convert the VMDK files to QCOW2 (more info)

qemu-img convert -f vmdk -O qcow2 disk1.vmdk disk1.qcow2

Repeat the same for disk2 and disk3, on the end you will have 3 files disk1.qcow2, disk2.qcow2 and disk3.qcow2

Load all 3 files using glance image-create ... (more info)

After completion of the loading, create volumes (go to images, under more you will see create volume) from the disk2 and disk3, size has to be similar to VMware size.

Launch instance from disk1.

Go to volumes, select disk2 and choose edit attachments, attach to the new instance (disk1), repeat the same with disk3.

Good luck!