Step one:

Download your desired languages zip from https://translate.blesta.com/

• العربية, MA (ar_ma) 0% completed (download)
• العربية, SA (ar_sa) 16% completed (download)
• bòsanskī, BS (ba_bs) 19% completed (download)
• български, BG (bg_bg) 1% completed (download)
• বাঙালি, BD (bn_bd) 0% completed (download)
• československý, CZ (cs_cz) 1% completed (download)
• dansk, DK (da_dk) 89% completed (download)
• Deutsch, DE (de_de) 93% completed (download)
• Ελληνικά, GR (el_gr) 13% completed (download)
• English, UK (en_uk) 58% completed (download)
• Español, ES (es_es) 77% completed (download)
• Español, SV (es_sv) 1% completed (download)
• فارسی, IR (fa_ir) 1% completed (download)
• Finlande, FI (fi_fi) 0% completed (download)
• français, FR (fr_fr) 97% completed (download)
• עברית, IL (he_il) 2% completed (download)
• Hrvatski, HR (hr_hr) 2% completed (download)
• Magyar, HU (hu_hu) 72% completed (download)
• Bahasa indonesia, ID (id_id) 44% completed (download)
• italiano, IT (it_it) 23% completed (download)
• 日本語, JP (ja_jp) 8% completed (download)
• 한국어, KR (ko_kr) 1% completed (download)
• Lietuviškai, LT (lt_lt) 7% completed (download)
• Nederlands, NL (nl_nl) 47% completed (download)
• Norsk, NO (no_no) 27% completed (download)
• polski, PL (pl_pl) 37% completed (download)
• português, BR (pt_br) 92% completed (download)
• português, PT (pt_pt) 53% completed (download)
• Română, RO (ro_ro) 6% completed (download)
• Pyccĸий, RU (ru_ru) 29% completed (download)
• Slovenščina, SI (sl_si) 2% completed (download)
• svenska, SE (sv_se) 76% completed (download)
• Kiswahili, TZ (sw_tz) 1% completed (download)
• ภาษาไทย, TH (th_th) 2% completed (download)
• Türkçe, TR (tr_tr) 99% completed (download)
• اُردُو‎, PK (ur_pk) 0% completed (download)
• Tiếng Việt, VI (vn_vi) 14% completed (download)
• 中文, CN (zh_cn) 75% completed (download)
• 中文, TW (zh_tw) 3% completed (download)

Step two:

Unzip the downloaded zip and upload the language file to language folder of your Blesta root.

Step three:

Log into Blesta and navigate to [Settings] -> [General] -> [Internationalization] and click Install to install the language.

Step four:

Then navigate to [Settings] -> [General] -> [Localization] and select Default Language from drop-down.

Step five:

Save this change.

Done!