What three groups were involved in the Boer War?

The Boer War that took place in 1899 to 1902 was a conflict in which the British forces fought against the two Republics ( Boers of the Transvaal and the Orange free state) of South Africa. There were several reasons that led to this war, including the British Expansion and annexation of the Transvaal government, and the Boer's ( the Afrikaners - Descendants of the Original Dutch immigrants of South Africa) opposition to the British forces in the Transvaal.
Britishers in the initial phase of the War were unprepared and militarily vulnerable, hence, the Boers took the advantage of the situation and claimed their victory. Though, the arrival of a large number of British soldiers in the colonies made an ultimate Boer defeat in early 1900. They overwhelmed the Boer army in the field. This war recorded its most destructive phase when the Boers used the Guerilla tactics under the leadership of Christiaan Rudolf de Wet and Jacobus de la Rey at the end of 1900. Therefore in response to this, the British army under Lord Kitchener began to destroy the field and that they kept the inhabitants in horrific conditions under the isolated camps.
At last this war came to end at the Peace Treaty of Vereeniging of 1902 when the Boers accepted the loss of their independence.

There were two Boer Wars—the first took place in 1880–1881, and the second took place in 1899–1902. The background of the wars was that the Afrikaners, the descendants of Dutch settlers from the seventeenth century, were pushed northward out of the British Cape Colony to the interior of South Africa. There, they existed as farmers in the independent states of Transvaal and the Orange Free State. When the British tried to annex these states in the 1870s, the Boers, as the Dutch were also called, revolted. The Boers were also involved with fighting the black South Africans in Zululand and Bechuanaland. The first war ended in a Boer victory and continued independence, while the second ended in a British victory that helped provoke a sense of nationalism among the Boers. Black South Africans were involved in the wars in noncombat roles (and later in combat roles in the British forces). Therefore, the three groups involved were the Boers, black South Africans, and the British.