You can find the online documentation for TIBCO products (including TSSS and TERR) using keyword searches of our docs site:
https://docs.tibco.com/
For example, the User Guide for TIBCO Spotfire Statistics Services (TSSS) 7.11.1 is at the following URL on the docs site:
https://docs.tibco.com/pub/sf_statsvcs/7.11.1/doc/html/TIB_sf_statsvcs_7.11_User-Guide/GUID-F8894BED-223F-480C-B426-5F55E13EDC40.html
TSSS 7.11.1 ships with TIBCO Enterprise Runtime for R (TERR) 4.5.0 as its default statistical engine. The online documentation for TERR 4.5.0 is at the following URL:
https://docs.tibco.com/pub/enterprise-runtime-for-R/4.5.0/doc/html/TIB_terr_Documentation/suitehelp_topic_list.html
It is particularly important to read the Release Notes for TSSS 7.11.1 and TERR 4.5.0, because they introduce new features that help administrators limit the use of system calls from inside the applications. The Release Notes are at the following URLs:
https://docs.tibco.com/pub/sf_statsvcs/7.11.1/TIB_sf_statsvcs_7.11.1_relnotes.pdf
https://docs.tibco.com/pub/enterprise-runtime-for-R/4.5.0/doc/html/TIB_terr_Documentation/GUID-5489474A-3A6B-479C-BB37-0DA193B12C25.html
The open-source R community's CRAN website (https://cran.r-project.org/) has links to manuals and introductory tutorials for R, which are also useful for reference when learning to program in TERR.