Question about Microsoft On-Hire Stock Award

I recently got an offer from Microsoft. The stocks part sounds little amgious: You will be granted On-Hire Stock Award of shares of Microsoft Corporation, USA, common stock, subject to approval by the Compensation Committee of Board of Microsoft Corporation, USA (or its delegates). The number of shares granted will be calculated by dividing the USD X (USD) specified in your offer letter, by the closing Microsoft stock price on a future date as per Company policy in vogue (typically the 15th of the month immediately following the month in which your start date occurs). On-Hire Stock Awards are generally approved on a monthly basis, with commencement of the On-Hire Stock Award on the approval date. All awards and grants are subject to acceptance of the 2017 stock award plan terms and conditions. The value of MS Corp shares vested is treated as a taxable perquisite and is subject to applicable withholding taxes. The stocks will be vested over a period of 4 years. My question is, do I have to buy these stocks every year like in some startups at X/4 price, or are they bought my MS and given to me? I assume it is latter, but just in case. #microsoft #stocks