Gita : Ch-12. Slo-9.

Srimad  Bhagavad-Gita :
Chapter-12. ( Bhakti-yogam )
Slokam,-9. (  Arjuna,  if you cannot fix your mind upon Me without deviation, then follow the regulated principles of bhakti-yogam, In this way you will develop a desire to attain to Me. )

atha  cittam  samadhatum  na  saknoshi  mayi  sthiram,

abhyasayogena   tatah  mamicchaptum  dhananjaya.

dhananjaya  =  hey  Arjuna!
atha  sthiram  samadhatum  =  hereafter,  permanaently  holding;
cittam   mayi  =  your  cittam  ( mind )  unto  ME;
na  saknoshi  =  if  you  are  not  capable;
tatah  abhyasayogena  =  then,  with  the  help  of  yogam  of  practice;
mam  aptum  icch  =  hence,  you  have  a  will  ( desire)  to  attain  Me.

If one is unable to focus their mind steadily on the Supreme Lord Krishna without distraction and interruption then one should continuously endeavour to perform abhyasa yoga which is repeatedly fixing the mind on the Supreme Lord while simultaneously restraining oneself from all worldly affairs.

Reflecting on Lord Krishna being the quintessence of all wonderful qualities and exalted attributes such as love, beauty, compassion, sweetness, wisdom, majesty, courage, valour, etc. while realising that He alone is the Supreme Lord of the spiritual kingdom and the material worlds being the ultimate source and the ultimate goal of all things at the same time being the antithesis and antidote of all that is demoniac and unrighteous.

True endeavour for the Supreme Lord is bhakti or exclusive loving devotion to Lord Krishna.
By remembering and meditating constantly on Him in this way, steadiness and equanimity of mind is achieved and one will directly realise themselves how to attain Him.

If one is however unable to focus their consciousness on the Supreme Lord Krishna in unmotivated devotion in a steady manner then there is an easier method to reach Him and that is to gently bring the distracted mind back to focus on Lord Krishna everytime it seeks to wander and roam towards other objects and ideas.

Again and again continuously one must seek and strive to attain Him through this yoga or the science of the individual consciousness attaining communion with the ultimate consciousness by constantly attempting to remember of the Supreme Lord.

Now Lord Krishna presents an alternative method for those who have not the equanimity of mind to continuously think of Him without distraction.

He instructs to strive to remember Him while restraining the mind from pursuing worldly affairs through repeated practice of meditating on His divine glories such as His infinite beauty, sweetness, power, compassion etc. or by chanting His holy names with affection and blissfully singing hymns to His glories.

The particle atha meaning and if emphasises there is another option.
To be continued  ....