Three Tasbeehs (A very primary and simple Tasbeeh/Zikr for the all people, which the Ulama/pious scholars have determined in the light of the Holy Quran and Hadith is an immense means of blessings, rewards, and the food for the soul).
These tasbeehs should are to accomplished twice a day – before/after Fajr and before/after Asr; otherwise, do it at least twice at any time of the day – InshaAllah; twice in a lunar day, i.e. right from one sunset to before-another sunset.
The three tasbeehs are as following:
100 times Istighfar – such as: استغفر الله (Astagfirullah) or ربي اغفر لي (Rabbigfirli) – or any Istighfar (from the Holy Quran or Hadith).
100 times Salaam and Salawaat (Durood Shareef) – such as: صلى الله عليه وسلم (sallallahu alayhi wa sallam) – or anyone durood Shareef (it is better to recite the Salaam & Salawaats mentioned in the Hadith).
100 times سُبْحَانَ اللَّهِ وَالْحَمْدُ لِلَّهِ وَلاَ إِلَهَ إِلاَّ اللَّهُ وَاللَّهُ أَكْبَرُ SubhanAllah wal Hamdulillah wa La-ilaha illallahu wallahu Akbar (It can also be read separately:- 100 times SubhanAllah, 100 times Alhamdulillah, 100 times La-ilaha illallah, 100 times Allahu Akbar).
That means you will read a total of ‘600 times’ every day.
* If someone reads the whole tasbeeh (i.e. 600 times) in one sitting due to busyness in the rest of the day or some other reason, s/he would be at least be benefitted InshaAllah.
** It is better to read the tasbeeh with ablution, sitting, paying attention.
*** To start the habit, accomplish it whilst walking, no problem. However, it is better NOT to make it a regular habit to read them while walking
**** If you ever miss the tasbeeh, do it at any time at night or before Zuhr the next day as a compensation, InshaAllah.