Your best bet is following instructions in release notes - http://support.f5.com/kb/en-us/products/big-ip_ltm/releasenotes/product/relnote-ltm-11-4-0.htmlrn_install_overview. You will need to upload the full 11.4.0 release to the LTMs, too (HF is only a roll-up of hotfixes for the main release).
A few other tips:
- upload a current qkview to ihealth and review any notices that could impact your upgrade (for example, httpclass profiles go away in v11.4+)
- open a proactive support case before your upgrade (~1 week in advance) in the event you have upgrade issues