Mounting these partitions is a two step process:
First step is making sure that they have a filesystem on them. I am not sure what filesystem you are wishing to use (ext3, ext4, zfs, etc). This really depend on your needs and the database software vendor (if there is one) will be able to tell you exactly what filesystem type you should use.
To create an ext3 filesystem which will likely be your best bet you would run the following command as root
mkfs -t ext3 /dev/mapper/vg_cluster_lv_rootp1
You will want to run this for each new partition that you created and this will put the ext3 filesystem on these partitions.
Next you will want to create the directory where you plan to mount these:
These are just examples -- choose whereever you want to mount these and obviously skip this step if you already know where you want these new partitions mounted.
Now you will mount using the mount command, again as root.
mount [your-partition] [mount-point]
mount /dev/mapper/vg_cluster_lv_rootp1 /date
To ensure that these auto-mount when you restart your system you need to add these mount points to your /etc/fstab file. Again open this file as root using your favorite text editor
Add lines for ach of your new mount points
/dev/mapper/vg_cluster_lv_rootp1 /data ext3 defaults 0 0
This should get your going, the filesystem or fstab options may vary based on your needs.